Various types of apparatuses are known in the art which effect the purification of gases by the removal of polluting substances by scrubbing with a suitable liquid. Among these may be mentioned scrubbing columns, cyclone scrubbers and Venturi type scrubbers.
These latter apparatuses comprise a Venturi tube through which a gas is made to pass and into the throat of which is sprayed the scrubbing liquid. Through the effect of the high gas velocity, the liquid is finely atomized and the intimate contact achieved allows good dissolution of the soluble pollutants and good capture of the insoluble pollutants. The Venturi tube is connected to a cyclone in which the liquid droplets together with the entrained impurities are eliminated.
However, the effectiveness of Venturi scrubbers drops when the dimensions of the particles of the pollutants fall to micron levels, since these tend to be expelled in the form of an aerosol.